Method for supplying articles and apparatus therefor

ABSTRACT

There is disclosed an apparatus and a method for feeding articles, the apparatus containing a tape transporting apparatus, including a transporting member having plural containing portions in succession, a cover tape for covering the apertures of the containing portions of the transporting member, a first reel for simultaneously winding the transporting member and the cover tape, a second reel for winding the transporting member only, a third reel for winding the cover tape only, a drive assembly for rotating the first, second and third reels, intermittent drive unit for driving the transporting member, control unit for driving the drive assembly and intermittent drive unit, an aperture for loading or removing the articles into or from the containing portions of the transporting member, a first detector for detecting the presence or absence of the article in the containing portion, and a guide member for defining the position to an article assembling apparatus or an article manufacturing apparatus, wherein each of these apparatus is provided with a robot hand and a main control unit to be connected to the control unit mentioned above.

This application is a continuation-in-part of application Ser. No.07/797,931 filed Nov. 26, 1991, now abandoned, which is a divisional ofapplication Ser. No. 07/503,745 filed Apr. 3, 1990, now U.S. Pat. No.5,090,113, which issued Feb. 25, 1992.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method for supplying an automaticapparatus for assembling or working such as a robot with articlestherefor, and more particularly such supply method in which saidarticles are stored or supported in a tape-shaped supply member and saidsupply member is supplied in the form of a reeled cassette.

Related Background Art

For the recent progress of factory automation, there have been proposedvarious automatic assembling apparatus, but the major technical targetto be solved in such apparatus is the rapid, secure and inexpensivesupply of articles (component parts) to be assembled.

The most commonly employed method of component supply to the automaticassembling apparatus is so-called pallet method, of preparing pallets inconsideration of the shape, weight and material of the parts to besupplied, arranging said parts in advance on said pallet, thentransporting said pallet to a predetermined position, and taking outsaid parts in succession from the pallet by the automatic assemblingapparatus for assembly therein. Such pallet method is applicable to andeffective to a certain extent in large component parts, but small partssuch as screws are too small for handling in such pallet method and aretoo many in number for such pallet method.

Even if the pallet method is to be applied to the small parts such asscrews, there will have to be handled a tedious job of properly aligningsuch small parts on the pallet.

In consideration of such inconvenience, there is often employed, forsuch small parts, a vibration part feeder method in which the smallparts are loosely contained in the container, and arranging said partsin one direction and aligning said parts for enabling one-by-one supplythereof, by the vibration of the container.

However, said pallet method or the vibration part feeder method isassociated, in case of supplying plural kinds of parts, with a drawbackof requiring pallets or feeders matching the shapes of such plural kindsof parts.

A cassette method for avoiding the above-mentioned drawbacks has beenproposed by the Japanese Laid-open Patent Sho 60-48855, in which partsare contained in continuous manner in a cassette, as shown in aperspective view in FIG. 4A.

More specifically, as shown in FIG. 11, a cassette case 100 indicated bya chain line is provided therein with three studs S rotatably supportingreels 103, 105, 104, wherein belts 101, 102 which can be adhered andseparated plural times are wound on said reel 103.

In said cassette 100, articles 109 to be supplied are in advancesandwiched between the belts 101, 102, and wound on the reel 103.

By rotating the winding reels 104, 105, the belts 101, 102 are taken upalong rollers 106, 107, 108 to expose the article 109 sandwichedtherebetween, and said article 109 can be taken out for example by arobot hand and used for example for the assembling work.

Also for supplying a robot for assembling or working an article withsaid articles, there have been proposed various methods.

The Japanese Patent Publication Sho 63-59813 discloses a structureconsisting of a robot running on an endless rail, a peripheral apparatusfor working or assembling in cooperation with said robot, and anapparatus for centralized control.

Also the Japanese Laid-open Patent Sho 51-128775 discloses an automaticassembling apparatus including a reciprocating table having apredetermined moving trajectory, and a part supplying apparatus, aworking/assembling machine etc. positioned in concentrated manner closeto the trajectory of said reciprocating table, wherein a manipulatorprovided on said reciprocating table takes a part from said partsupplying apparatus and feeds it to the working/assembling machine toeffect the required assembling work.

SUMMARY OF THE INVENTION

A first object of the present invention relates to an articletransport/feeding apparatus in which articles are contained in articlecontaining portions formed in an article transporting member such as atape which is contained in a cassette, and is to provide an articletransporting apparatus employing a tape, capable of exact positioning ofthe articles on the transporting member such as tape, thereby enablingthe handling of said articles for example by a robot, also not requiringthe replacement of said tape and not generating slack in said tape atthe winding thereof, thereby enabling secure transportation of thearticles.

It is also an object to provide an article transporting apparatusemploying a tape, enabling the detection of presence or absence of thearticle immediately before the operation of the robot hand, therebyavoiding the wasted operation in the robot hand, such as a pickup error.

A second object of the present invention relates to a system for workingor assembling the article employing the article transporting apparatusof the present invention for feeding said articles to a robot.

In an assembling/working system in which plural tape cassettesincorporating articles are arranged along the running path of a robotand the assembling or working operation is conducted by receiving thearticles in succession from said tape cassettes by the robot, thereoccurs a pickup failure by the robot hand in the assembling or workingoperation by the robot by picking up the article supported by thetransporting member in the tape cassette.

Such pickup failure is caused for example by the absence of the articlein the transporting member of the tape cassette.

In the system with plural tape cassettes arranged along the running pathof the robot, for effecting the assembly by picking up the articles insuccession from said tape cassettes, 50 articles are loaded in each tapecassette, for example in order to assemble 50 products in a continuousoperation. In such case, the eventual absence of an article in any ofthe cassettes gives rise to an error in the production schedule, or adefect in the assembled product.

The above-mentioned object can be achieved, according to the presentinvention, by a method of storing articles in continuous manner in atransporting member and supplying said articles in succession to anarticle feeding position, utilizing a working station for effecting theassembling or working operation by a first robot by feeding saidarticles thereto in a state stored in said transporting member, and anarticle loading station provided with a second robot for storing saidarticles in said transporting member, wherein the information on thenumber of articles in said working station is transmitted to saidarticle loading station thereby correcting the loading of articles.

Also the present invention proposes an effective method for supplyingthe robot with the articles carried by tapes, by arranging, along therunning path of the robot, plural tape cassettes each containing acarrier tape carrying said articles.

The present invention also proposes a method, in the cable communicationbetween the robot and the supply apparatus or peripheral apparatus, foravoiding the problems related to cable wiring, particularly cable wiringmethod, breakage or defect in electric wiring and complication inelectric wiring.

Furthermore the present invention proposes a method of supplyingdifferent articles by plural tape cassettes, according to the procedureof assembling or working by robot, in which, in the access of the robotto each of plural tape cassettes, the robot recognizes the functionstatus of each tape cassette by a signal therefrom and functionsaccordingly.

In a system as disclosed in the aforementioned Japanese Laid-open PatentSho 60-48855, in which the aforementioned assembling/working apparatusis combined with a tape cassette containing a tape carrying the articlesfor successive removal of said articles by rewinding of said tape, theremay eventually result the failure of loading of the article in thestorage position on the tape, in the course of loading process, forexample by the feeding of the tape without a pickup operation by theloading robot.

The assembling or working of the article is not conducted if the articleis not contained in the storage position of the tape.

Also in a system for effecting an assembling operation by picking updifferent articles from plural tape cassettes positioned along therunning path of the robot, the assembling of a complete product cannotbe achieved if the article is absent in the storage position of thetape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the basic principle of storage andremoval of a component part P into and from a tape;

FIG. 2 is a lateral view showing the schematic structure of anembodiment of the tape-carried article transporting apparatus 50;

FIG. 3 is an external view of a driving assembly 13 of a part mountingreel 6 in rotary means;

FIG. 4A is a perspective view showing the mode of setting thetape-carried article transporting device 50 into an assembling apparatusM equipped with a robot hand H;

FIG. 4B is a perspective view showing the mode of setting thetape-carried article transporting device 50 into a part manufacturingapparatus N equipped with a robot hand H;

FIG. 5 is a flow chart showing the function of an embodiment of thepresent invention;

FIG. 6A is a block diagram of a tape cassette controller and a robotcontroller;

FIG. 6B is a detailed block diagram of a logic circuit 64;

FIG. 7 is a chart showing bit signals representing the work status;

FIG. 8 is a schematic view of a sensor 20;

FIG. 9 is a schematic view of the entire system;

FIGS. 10A, 10B and 10C are views for explaining the signal conversion;and

FIG. 11 is a schematic view of a conventional tape cassette.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now the present invention will be clarified in detail by preferredembodiments thereof shown in the attached drawings.

1) Carrier Tape

FIG. 1 shows the basic principle of storage and removal of a componentpart into and from a tape constituting the transporting member A carriertape 3 is provided, in succession and with a constant pitch, withrecesses (storage portions) 3a of which internal dimensions (depth,width and height) are slightly larger than the external dimensions ofthe component part P. Also the carrier tape 3 is provided, along lateraledges thereof, with perforations 3b in successive manner, which engagewith a sprocket 12 for transmitting the driving force to the carriertape 3. A cover tape 5 is provided for covering, as illustrated, thecomponent part P set in the recess 3a thereby maintaining the componentpart P in the set position in the recess 3a and rendering said part Premovable.

When the carrier tape 3 and the cover tape 5 are moved in a directionindicated by a broken-lined arrow, the component part P is moved asindicated by a broken-lined arrow, then set in the recess 3a of thecarrier tape 3, and is covered on the upper face by the cover tape 5. Onthe other hand, when the carrier tape 3 is moved in a directionindicated by a solid-lined arrow and the cover tape 5 is also moved asindicated by a solid-lined arrow with deflection by a guide roller 17rotatably supported on a stud S, the component part P is exposed in theupper part thereof and is thus rendered removable. After the componentparts P are stored as explained above, the carrier tape is wound on areel for effecting continuous storage and supply operations.

2) Structure of Apparatus

FIG. 2 is a schematic lateral view of an embodiment of the tape-carriedarticle transporting apparatus 50, in which the above-mentioned carriertape 3 and cover tape 5 are wound in reels.

A base plate 1 formed from a plate material is integrally provided withan unrepresented reinforcing member, thereby having a strength enoughfor supporting all the following components on one side. Studs S areperpendicularly provided on an unrepresented frame integral with thebase plate 1, for rotatably supporting reels and wheels.

The carrier tape 3, with the parts P carried in the recesses 3a asexplained above and with the cover tape 5 covering the apertures of saidrecesses 3a is wound on a part mounting reel 6. A part mounting reel 6,a cover tape reel 8 for winding and feeding of the cover tape 5, and atape reel 7 for winding and feeding of the carrier tape 3 are renderedrotatable about the studs S. The ends of said tapes are fixed by fixingparts 6d, 7d, 8d of the central cores 6c, 7c, 8c of said reels, and saidtapes are respectively wound on the peripheries of said cores 6c, 7c,8c. These reels are respectively provided with rotating means, whichtransmit the rotating force by contact with the external peripheries ofsaid reels.

Thus the part mounting reel 6, tape reel 7 and cover tape reel 8 arerespectively provided with rotating means for transmitting the drivingforce to said reels.

FIG. 3 is an external view of a driving assembly 13 for the partmounting reel 6. The following description will be concentrated on saidassembly 13, but it is to be understood that similar driving assemblies14, 15 are respectively provided for the tape reel 7 and the cover tapereel 8.

Referring to FIG. 3, a motor 13a for driving the tape and giving tensionthereto is provided, on both ends of the shaft thereof, with rubberrollers 13b of urethane rubber. In order to maintain said rubber rollers13b with the external peripheries of hubs 6a, 6b of the reel 6 withbiasing force, said motor 13a is mounted on an end of an arm member 13crotatable supported about a stud S perpendicularly fixed on the baseplate 1.

A tension spring 13e is provided between the other end 13e of said armmember 13c and another stud S, thereby giving a clockwise biasing forceto said arm member 13c. Thus the peripheries of the rubber rollers 13bare maintained, with a biasing force, in contact with the peripheries ofthe hubs 6a, 6b of the reel 6, thereby frictionally driving the same.

Again referring to FIG. 2, the motors 13a, 14a, 15a are driven as willbe explained later, by wirings to a control unit 10 (shown in FIG. 6A),as indicated by double-dotted chain lines.

Said control unit 10 is incorporated in the tape-carried articletransporting device 50, and is automatically powered when said device ismounted in the assembling apparatus M or the part manufacturingapparatus N to be explained later.

The mounting of the tape-carried article transporting device 50 into theassembling apparatus M or the part manufacturing apparatus Nautomatically actuates a power switch SW1, and it is also possible toswitch the operating mode by a selector switch 10a.

A stepping motor 9, indicated by broken lines, is controlled by thecontrol unit 10 through wirings indicated by double-dotted chain lines.Said stepping motor 9 rotates a sprocket gears 12b of the sprocket 12rotatably supported by a stud S, through a belt 11 indicated by brokenlines.

Said sprocket 12 is provided, on the periphery thereof, with pins 12aengaging with the perforations 3b of the carrier tape 3, for advancingsaid carrier tape 3. Two sprocket gears 12b are integrally formed withthe sprocket 12 for engaging with two rows of perforations 3b of thecarrier tape 3.

Two part sensors 20 are positioned, between two sprockets 12, with apitch same as that of the recesses 3a and fixed on the base plate 1, forcounting and detecting the presence of the component parts. Said sensors20 are composed of light-emitting elements and photosensors 20a, 20a',20b, 20b ' (photosensors 20a', 20b ' being not shown), for projectinglight to the stored article through the translucent part of the carriertape 3 and receiving the reflected light.

A guide roller 16, rotatably supported by a stud S on the base plate 1,serves to deflect the carrier tape 3 from the vertical direction to adirection toward the sprockets 12, as shown in FIG. 2.

Another guide roller 17, similarly supported, serves to deflect thecover tape 5 from a direction toward the sprockets 12 to a directiontoward the part mounting reel 6.

A curved guide rail 18 provided on the base plate 1 serves to guide thecover tape along the curved face thereof.

Paired cam followers 19 rotatably supported by studs S at the left andright ends of the base plate 1 serve as guide members in relativepositioning at the mounting of the article transporting device 50 in theassembling apparatus M or the part manufacturing apparatus N.

FIG. 4 is an external perspective view showing the mode of mounting ofthe tape-carried article transporting device 50 in the assemblingapparatus M or the part manufacturing apparatus N equipped with a robothand H. After being inserted into a mounting unit 22 integral with theassembling apparatus M or the part manufacturing apparatus N, the deviceis set in a predetermined position by the engagement of the camfollowers 19, serving as the relative positioning guide members, withengaging grooves 22a of said mounting unit 22.

The robot hand H provided on said apparatus M or N is so controlled, aswill be explained in relation to the flow chart, as to feed the part Pmanufactured by the apparatus N to the empty recess 3a of the carriertape 3, or the part P stored in the recess 3a of the carrier tape 3 tothe assembling apparatus M.

3) Flow Chart

In the following there will be explained the function of the presentembodiment, with reference to a flow chart shown in FIG. 5, and blockdiagrams shown in FIGS. 6A and 6B.

1. Mounting of tape cassette 50 to cassette holder

A tape cassette 50A₁ is subjected, in an article loading station shownin FIG. 4B, to the loading of articles molded in a molding machine inthe recesses 3a, 3a, ... of the carrier tape 3, and, after the loadingof a predetermined number of articles P₁, P₂, ..., is mounted on acassette holder 22 shown in FIG. 4A (step S1).

The number of articles atored in the tape cassette 50A₁, variabledepending on the product to be assembled or worked or the number ofarticles required in each product, is memorized in a counter C1 of thecontroller 10 of the tape cassette. When the tape cassettes 50A₁, 50A₂,... are mounted on the cassette holders manually or automatically, thereis conducted communication with the controller of the robot. When acassette is mounted on the cassette holder, a mounting detection switchSW1 positioned between said tape cassette and said cassette holder isturned on (step S2). In response to the signal from said switch SW1, asignal A indicating the completion of mounting is supplied to alight-emitting circuit LEC, which converts said signal A into acorresponding pulse signal causing the light-emitting element LE torelease a mounting completion signal A (step S3).

Upon mounting of the tape cassette 50A₁ on the cassette holder,simultaneously with the closing of the switch SW1 provided between thetape cassette 50A₁ and the cassette holder, an initial state operationsignal B of the tape cassette is supplied to motor drive circuits 13A,14A, 15A for the tape feeding motor 13a, tape winding motor 14a andcover tape motor 15a. Upon completion of the loading of the articlesinto the recesses of the carrier tape in the article loading station,the cover tape is laid on the last article holding aperture of thecarrier tape, and the carrier tape 3 and the cover tape 5 are slightlytaken up in order to prevent the loss in the articles. For this purposeit is necessary to mount the tape cassette 50A₁ in the cassette holderand to fully reverse the carrier tape toward the feeding reel, in orderto place the first article storage recess at the article pickup position(Xl--Xl in FIG. 1) by the robot hand. Initial state operation signalgenerating means 60 releases, in response to the signal from said switchSW1, said initial state operation signal B for activating the motordrive circuits 13A, 14A, 15A for predetermined periods, for defining thefirst recess containing the article at the position for removal (stepS4).

The operation signal B from the generating means 60 activates a sensoroperation circuit 20A for the sensors 20 constituting the articledetecting means. In the present embodiment, said sensors 20 are composedof two sets of light-emitting element and photosensor, of which thelight-emitting elements 20a, 20b emit light in response to a signal fromthe operation circuit 20A. If the light is intercepted by the firstarticle stored in the translucent tape, the photosensors 20a', 20b ' donot receive the light and a first logic signal "1" is released from anAND gate (step S5).

When the carrier tape is advanced by the rotation of motors so that thearticle in the first recess is brought to the removing position wherethe robot hand H effects the pickup operation, the photosensors of thesensors 20 activated in said step S5 generate a detection signal.

In response to the signals from the photosensors 20a', 20b', the ANDgate in the logic circuit 64 releases a logic signal "1", therebydeactivating the motor drive circuits (step S6).

Said detection signal from the sensor 20 is supplied to a bit signalforming circuit 62, for generating a signal C, which is transmitted tothe robot through a light-emitting circuit LEC, a light-emitting elementLE and a photosensor of the robot (step S7).

A controller 70 of the robot sends the signal received by thephotosensor LR to a signal conversion circuit 72A, of which outputsignal is supplied to an operation state discriminating circuit 72B.Said circuit 72B identifies the received signal as indicating thepresence of an article in the removal position, and sends a pickupcommand to the robot hand H (step S8).

When the recess of the carrier tape 3 is evacuated by the article pickupoperation of the robot hand H, the first sensor is turned off while thesecond sensor is turned on, whereby a second AND gate 64B of the logiccircuit 64 releases a signal indicating the absence of article (stepS9).

Said signal is supplied to the bit signal forming circuit 62 and themotor drive circuit, and said circuit 62 releases a signal D indicatingthe end of pickup operation.

Said signal D from the bit signal forming circuit, indicating theabsence of the article in the recess at the removal position andprohibiting the pickup operation by the robot hand H, is transmitted tothe robot through the light-emitting element LE and the photosensor LRof the robot (step S10).

In response to the signal from the logic circuit 64 in the step S9, themotors are activated to advance the next article to the removal position(step S11).

In the step S9, when the photosensor 20a ' releases the signalindicating the absence of article at the end of the pickup operation ofthe robot hand, the aforementioned counter C1 is subjected to adecrement (step S12).

Said counter C1 of the tape cassette indicates the remaining number ofarticles by a display unit 76.

Thereafter repeated are the detection of article at the removal positionby the sensor 20, pickup of the article, decrement of the counter C1,and advancement of the carrier tape (step S12).

When the number of remaining articles in the carrier tape in the tapecassette reaches a predetermined number, a warning signal is releasedfrom output means 78, for giving a warning to the operator for thepreparation of exchange of the tape cassette (step S13).

More specifically, when the remaining number of the counter C1 reaches apredetermined value, a remaining number signal N is sent therefrom tothe bit signal forming circuit, which causes the robot to display thewarning information through the light-emitting element LE and thephotosensor LR of the robot (step S14).

After such warning for example at a remaining number of 50 articles,when the last article reaches the removal position, the first and secondsensors 20 are respectively turned on and off, of which signals aresupplied to a third logic OR gate 64C. The output signal of said OR gateand a signal indicating N=1 in the counter C1 are supplied to a finalarticle confirming circuit 80, of which output signal is entered to thebit signal forming circuit 62, whereby a bit signal E, indicating thelast article on the carrier tape is transmitted, through thelight-emitting circuit LE, to the robot controller 70 (step S15).

In response, the robot controller sends a pickup command to the robothand (step S16).

Upon pickup of the last article by the robot hand, the first and secondsensors release logic signal "0", which are sent to a fourth logic NANDgate 64b, thus generating a signal indicating the absence of the lastarticle on the carrier tape. Said signal is supplied to the bit signalforming circuit 62, which sends, to the robot, a signal F indicatingthat the articles on the carrier tape are completely used up.

4) Skipping Operation of Recess of Carrier Tape (Loading FailureConfirming Mode)(step S5')

In the loading of the articles P1, P2, ... into the recesses 3a, 3a, ...of the carrier tape, there may result a loading failure for some reason.The apparatus of the present embodiment has a skipping function ofdetecting an empty recess in the consecutive recesses of the carriertape by detection means, and skipping such empty recess by furtheradvancing the carrier tape in response to a signal from said detectionmeans.

If, as shown in FIG. 8, an article is present at the removal positionbut the next recess is empty, the photosensor 20a ' of the first sensorreceives the light from the light-emitting element 20a reflected by thearticle and generates a signal, but the photosensor 20b ' of the secondsensor does not release the signal due to absence of the article. Thesignals from said first and second photosensors are supplied to a fifthlogic EXCLUSIVE OR gate 64E constituting a skipping confirming means.

The output signal of said EXCLUSIVE OR gate 64E is supplied to the motordrive circuit, whereby the empty recess of the carrier tape is notstopped at the removal position, and the carrier tape is furtheradvanced until a next recess reaches the removal position.

5) Transmission of Corrective Information to Molder at Loading Failure

The system of the present embodiment is so constructed, as shown in FIG.9, that plural cassette holders are positioned along the running path ofthe assembling/working robot. The tape cassettes loaded in the loadingstation are mounted on said cassette holders, and, when the robotreaches the position of each tape cassette, the robot makes access tosaid tape cassette by optical communication between the controller ofsaid cassette and that of the robot. The robot thus executes theassembly or working of the articles by picking up said articles insuccession.

In such assembling operation of a product or a unit by successivepick-ups of the articles from the tape cassettes, the number of articlesrequired for said product or unit becomes unmatched if the loadingfailure happens in a particular cassette, for example No 2. Inconsideration of such situation, the present embodiment is provided witha function, in case the above-explained skipping operation is conductedat least for a predetermined number, of sending a signal from the robotcontroller to the controller of the molding station, in order to effectadditional loading of articles in the carrier tape of the correspondingcassette.

More specifically, the signal from said skipping confirming means 64E issupplied to the bit signal forming circuit, which sends a skipping bitsignal G to a counter C2 of the robot controller. Upon receiving saidsignal G by a predetermined number, the counter C2 causes supplementinformation generating means 80 to send supplement information to themolding station, which, in the loading of articles into the cassette No.2, effects supplemental loading, corresponding to the preceding loadingfailures, on the carrier tape of the cassette No. 2.

More specifically, said supplement information is sent to a controller90 of the loading station shown in FIG. 4B.

Said controller 90 of the loading station is provided with a counter C3for counting the number of operations of the loading robot of receivingthe article from the molding apparatus and storing said article into therecess of the carrier tape. Upon completion of loading for example of100 articles in response to a command for loading 100 articles in thetape cassette No. 1, the counter C3 releases a count out signal toprohibit the loading operation of the loading robot.

The counter C3 of the controller 90 of the molding station functions inthe following manner:

i) Ordinary Mode

The counter effect addition or subtraction by counting the number ofloading operations of the loading robot of the molding station. In caseof substraction, when the number of loading operations reaches 100, thecounter C3 releases a count out signal to terminate the loadingoperation. In response an unrepresented display unit displays thecompletion of loading of the tape cassette No. 1.

ii) Correction Mode

For example if the count of the aforementioned skipping counter C2 is10, the robot controller 70 sends, to the controller 90 of the moldingstation, information for loading 10 additional articles into therecesses of the carrier tape of the tape cassette No. 1. In response thecounter C3 of the controller 90 is set at an initial count 100+10=110.

The counter C3 effects subtractions corresponding to the number ofloadings of the loading robot, and releases a count out signal toterminate the loading operation when the number of loadings reaches 110.

In such correction mode, if the counter C3 is set for example at 110 inresponse to the information from the supplement information generatingmeans 80, the display unit may display said number "110" to inform theoperator of the supplemental loading of 10 articles.

6) Optical Communication

The robot of the present embodiment recognizes the operation state ofeach tape cassette by the operation state discriminating means 72B, fromthe bit signal A-G shown in FIG. 7, by receiving the light signal fromeach accessed one of the cassettes 50A₁, 50A₂, ... and accordinglycontrols the functions of the robot hand H and the robot itself.

FIGS. 10A and 10B respectively show a signal conversion circuit 62A ofthe cassette for converting bit signals A, B, ... into light pulses, anda signal conversion circuit 72A of the robot.

The structures and functions of said signal conversion circuits will beexplained in the following.

At first, in response to the counting of the tape cassette 50A₁ on thecassette holder 22, the switch SW1 is closed to activate the initialstate control signal generating circuit 60, of which signal is suppliedto the bit signal forming circuit 62. Thus a bit signal B, indicatingthe initial state, is supplied from said circuit 62 to a signalprocessing circuit 82 shown in FIG. 10A.

As shown in FIG. 10A, the signal processing circuit 82 is composed of aconverter 82A, an oscillator 82B, a frequency divider 82C, and an ANDgate 82D.

Said bit signal B is supplied to the converter 82A and converted into apulse encoded signal a₁ shown in FIG. 10C.

The frequency divider 82C divides the frequency of pulses of 6 MHz fromthe oscillator 82B to generate a pulse signal a₂ of 48 kHz shown in FIG.10C.

The outputs of said converter 82A and frequency divider 82C are suppliedto the AND gate 82D to obtain a pulse signal a₃ shown in FIG. 10C, whichis supplied to the light emitting circuit LEC of the opticalcommunication means L₁, whereby a light signal is sent from the tapecassette to the photosensor LR₁ of the robot.

When the tape cassette 50A₁ is in the initial state mode, and the robotis in access to said tape cassette 50A₁, the light-emitting meansthereof constantly sends said signal.

The controller of the robot receives the signal a₃ representing thefunction state of said tape cassette 50A₁ by the photosensor LR₁constituting the optical communication means L₁, and enters said signalinto the signal processing circuit 72A of the robot shown in FIG. 10B.

Said signal processing circuit 72A is composed of a counter 72a₁, atiming signal generator 72a₂, and a latch circuit 72a₃.

Upon receiving the light signal a₃ by the photosensor LR₁, the signalprocessing circuit 72A counts the number of pulses entered into thecounter within an interval of 10 msec defined by the timing generator,and stores said number in the latch circuit 72a₃.

After the robot reaches the access position to the tape cassette 50A butbefore the start of access operation, the robot read the signal fromsaid latch circuit 72a₃ and identifies the initial state mode of saidtape cassette 50A₁ from the signal B.

As explained in the foregoing, in case the number of articles to beconsumed in the assembling/working station is deficient, the supplementinformation obtained in said station is sent to the article supply(molding) station to achieve the supply of articles in consideration ofsuch deficiency, so that the present invention can securely recover thedeficiency of articles in the assembling/working station.

In order to solve the drawbacks explained above, the present inventioneffects optical communication between the robot and the tape cassetteincorporating the tape carrying the articles, whereby each tape cassetteemits a signal representing the function state thereof, and the robotrecognizes said function state upon arriving at the access position tothe tape cassette. By such optical communication between the tapecassette and the robot, the present invention avoids the cableconnection between the controllers of said tape cassette and the robotand the complications associated with such cable connection.

Also in the present invention, the function state of the tape cassetteis sent by a bit signal to the robot, whereby, even in an article supplysystem including plural tape cassettes arranged along the running pathof the robot, the robot controls its operation by recognizing the stateof the tape cassette by receiving the light signal. Thus thecommunication can be exactly conducted even in the presence of pluraltape cassettes, and the communication control system is not complicatedeven when the number of tape cassettes increases.

We claim:
 1. An article feeding method in which a tape supportingarticles is stored in a cassette, the cassette is mounted in a cassettemounting position of a robot, and the tape in the cassette istransported, thereby feeding the articles to an article pick-up positionof a robot hand, comprising steps of:supplying the articles to thepick-up position by mounting the cassette in the cassette mountingposition of the robot to transport the tape in the cassette;transmitting a light signal indicating an article feeding state of thecassette from a cassette sender to a robot receiver; and effecting apick-up operation by the robot hand at the robot on the basis ofreceiving the light signal.
 2. A method according to claim 1, furthercomprising the step of detecting presence or absence of the articlessupported by the tape in the cassette, wherein when the articles to befed to the pick-up position are absent on the tape and not supported bythe tape, feeding of the articles is effected with skipping a portionwhere the article is absent.
 3. A method according to claim 1, whereinsaid tape cassette is adapted, after being mounted in an interactiveposition with said robot, to convert plural function states of said tapecassette into a light signal, and communication between said tapecassette and said robot is conducted by a set of optical communicationmeans, whereby the robot can recognize the function state of said tapecassette.
 4. A method according to claim 1, wherein said tape cassettewith said feeding member loaded with said articles is adapted, afterbeing mounted in an interactive position with said robot, to enter aninitial state for advancing said feeding member in the tape cassette inorder to bring the first article to a position for pick-up by saidrobot, and to transmit said initial state to said robot by said opticalcommunication, whereby the robot can recognize the initial state of thetape cassette.
 5. A method according to claim 1, comprising stepsof:arranging plural tape cassettes along the running path of said robot,emitting a light signal from each tape cassette corresponding to thefunction state thereof; and effecting the article feeding operationaccording to the recognition of the function state of each tape cassetteby the robot, by reception of said light signal by the robot when itenters an interactive state with each tape cassette by the movement ofthe robot.
 6. A method according to claim 1, wherein after the pick-upoperation of the articles on the tape by the robot hand, a signal toprohibit another pick-up operation of the robot hand is transmitted fromthe cassette sender to the robot receiver to thereby effect prohibitingthe pick-up operation of the robot hand.
 7. A method of feeding articlesto an article feeding position while the articles are storedsuccessively in a transporting member, said method employing:a workstation for conducting an assembling or working operation by a robot towhich said articles stored in the transporting member are fed; and anarticle loading station for loading the articles in said transportingmember; said method comprising the steps of: detecting informationconcerning absence of an article when the articles are picked up fromthe transporting member by the robot in the work station; adjusting anumber of the articles loaded in the article loading station in saidarticle loading step on the basis of the information from the detectingstep.
 8. A method of feeding articles by an article transporting memberfor conducting, at a working/assembling station, working or assemblingof the articles manufactured at a manufacturing station,said methodemploying an article transporting apparatus for storing the articletransporting member in which the articles manufactured in themanufacturing station are stored, said method comprising the steps of:effecting winding-rewinding of the article transporting member;detecting presence of absence of the articles in the articletransporting member on the basis of operation of picking up the articlesby a robot in the working/assembling station; connecting mechanicallyand electrically the article transporting apparatus to theworking/assembling station; and effecting information interchangebetween the article transporting apparatus and the working/assemblingstation by light communication.
 9. A method of feeding articles by anarticle transporting member for conducting, at a working/assemblingstation, working or assembling of the articles manufactured at amanufacturing station,said method employing an article transportingapparatus for storing the article transporting member in which thearticles manufactured in the manufacturing station are stored, saidmethod comprising the steps of: feeding the article transporting member;detecting presence of absence of the articles in the articletransporting member; connecting mechanically and electrically thearticle transporting apparatus to the working/assembling station; andskipping one step of feeding the article transporting member on thebasis of a detection result of the detecting step.
 10. A method offeeding articles by an article transporting member for conducting, at aworking/assembling station, working or assembling of the articlesmanufactured at a manufacturing station,said method employing an articletransporting apparatus for storing the article transporting member inwhich the articles manufactured in the manufacturing station are stored,and means for counting a number of the articles stored in the articletransporting member, said method comprising the steps of: effectingwinding-rewinding of the article transporting member; detecting presenceof absence of the articles in the article transporting member, based onoperation of picking up the articles by a robot in theworking/assembling station; and effecting a count by the counting meansin response to picking up the articles from the article transportingmember which has been connected to the working/assembling station of thearticle transporting apparatus.
 11. An apparatus feeding articles by anarticle transporting member for conducting, at a working/assemblingstation, working or assembling of the articles manufactured at amanufacturing station,said apparatus comprising: an apparatus body;means for driving winding-rewinding of the article transporting memberin which the articles are stored; means for detecting presence ofabsence of the articles in an article picking up position of theworking/assembling station; means for connecting mechanically andelectrically the article transporting apparatus to theworking/assembling station mounted in the apparatus body; and lightcommunication means for effecting communication of a signal of operationof picking up the articles in the article transporting member betweenthe article transporting apparatus and the working/assembling station,on the basis of a signal from the detecting means.